Alcohol and drug abuse impose significant costs on society. In 1992, the economic cost of alcohol and drug abuse was estimated to be 246 billion dollars. The majority of these costs arise from alcohol abuse (148 billion dollars). Partly in response to these costs, new pharmacotherapies have recently been developed to treat alcohol abuse and alcoholism. Likewise, important advances have been made in the development of behavioral interventions designed to treat alcohol abuse. While new alcohol abuse therapies have been developed over the last several years, pressures have been developing to identify therapies that are not only efficacious but also cost-effective. Much of this pressure has been driven by managed care, which has placed a premium on economic studies that assess whether the clinical and economic outcomes of new pharmaceutical and behavioral therapies justify their costs. To increase the understanding of the efficacy of two pharmacotherapies (naltrexone and acamprosate) and psychotherapy, the National Institute on Alcohol Abuse and Alcoholism (NIAAA) recently funded Project COMBINE, a multi-site, randomized control trial (RCT). This trial is one of the most ambitious clinical trials ever undertaken for the treatment of alcoholism. However, in spite of the importance of economic analysis of clinical trials, the Project COMBINE protocol does not include cost or cost-effectiveness studies. The purpose of this study is to examine the costs and cost-effectiveness of behavioral and pharmacotherapies for alcoholism (and their combination) included in Project COMBINE. Our proposed project builds on Project COMBINE's RCT design, which will provide great credibility of our results in the scientific community. Because of the number of therapies studied, the strength of the study design, and the limited existing literature on the cost and cost-effectiveness of alcohol treatments, the proposed study represents a major advance in the cost and cost-effectiveness analysis of alcohol treatment; our results should have a profound effect on the choice of alcohol treatment in the United States.